This invention relates generally to pumps and in particular to those useful in the dispensing of fluids of the type found in vending machines.
Pumps of this nature are normally reciprocating in operation and comprise dual opposing chambers which alternately fill and void thereby facilitating the desired pumping operation. More specifically there is characteristically provided opposing inlet and outlet orifices in fluid communication with the dual pumping chambers, the orifices being provided with check valves which permit only unidirectional fluid flow. A pilot valve or similar structure is useful in redirecting a pump power medium thereby facilitating the reciprocating action of the fluid pump. It is well known that pumps of this nature, because of their reciprocating movement, are often prone to stall conditions thereby requiring some attendance.
Other pumps of this nature include motor-driven devices wherein a cam-type drive mechanism operates the reciprocating piston element thereby facilitating the pumping operation. It is well known that in pumps of this nature there is required certain pressure sensing and pressure relief devices to guard against harmful pressure peaks and their possible harmful effect on downstream components.